TW202136171A - Method for burning carbon-containing material in a pfcfr shaft kiln - Google Patents

Abstract

The present invention relates to a method for burning and cooling material, such as carbonate rocks, in a parallel flow - counter flow regenerative shaft kiln (10) having two shafts (12, 14) which are operated alternately as a burning shaft and as a regenerative shaft, wherein the material flows through a preheating zone (32, 34), at least one burning zone (50, 52), and a cooling zone (60, 62) to a material outlet (24, 26), wherein fuel is supplied in or above the preheating zone (32, 34), and therefore the fuel is heated in the preheating zone (32, 34) prior to entry into the burning zone (50, 52). The invention also relates to a parallel flow-counter flow regenerative shaft kiln (10) for burning and cooling material, such as carbonate rocks, having two shafts (12, 14) which can be operated alternately as a burning shaft and as a regenerative shaft, wherein each shaft (12, 14) has, in the direction of flow of the material, a preheating zone (32, 34) for preheating the material, a burning zone (50, 52) for burning the material and a cooling zone (60, 62) for cooling the material, wherein a fuel inlet (20, 22) for admission of fuel into the respective shaft (12, 14) is arranged above or inside the preheating zone (32, 34).

Description

Method for burning carbonaceous materials in GGR shaft furnace

Field of invention

The invention relates to a method for burning carbonaceous materials in a Gleichstrom-countercurrent-regeneration shaft furnace (GGR shaft furnace), and a GGR shaft furnace.

Background of the invention

For example, such a GGR shaft furnace known from WO 2011/072894 A1 has two vertical parallel shafts, which work cyclically, wherein only one shaft, namely the respective combustion shaft, is burned, and the other The shaft works as a regeneration shaft. The oxidizing gas is transported to the combustion shaft in the same direction as the material and fuel, where the hot exhaust gas generated here, together with the heated cooling air transported from below, is introduced into the exhaust shaft through an overflow channel, where the exhaust gas and the The material is discharged upwards in countercurrent and the material is preheated here. The material is usually fed into the shaft from above together with the oxidizing gas, where fuel is injected into the combustion zone.

The material to be burned usually passes through a preheating zone for preheating the material, a combustion zone connected to the preheating zone, and a cooling zone connected to the combustion zone in each shaft. The material is burned in the combustion zone, and the cooling zone The cooling air is delivered to the hot material.

During a cycle lasting, for example, 10-15 minutes, the material to be burned is continuously discharged on the two shafts through the discharge device. The column of material descends evenly in the shaft. Then, the furnace is switched so that the shaft previously used as a combustion shaft becomes a regeneration shaft, and the shaft previously used as a regeneration shaft becomes a combustion shaft again.

Such a GGR shaft furnace is operated with gas with a heating value up to about 3.3 MJ/Nm ^{3 , and the gas with a heating value less than 6.6 MJ/Nm 3} brings significant disadvantages in the operation of the GGR shaft furnace. For example, there is a high proportion of incombustible components in gas with a calorific value of less than 6.6 MJ/Nm ^3. As a result, a relatively large amount of gas is generated during the operation of the GGR shaft furnace, which, together with the combustion air and the lime cooling air, causes a large amount of exhaust gas. This larger exhaust gas volume contains a heat surplus that can no longer be absorbed by the limestone bed in the preheating zone of the GGR shaft furnace. As a result, the temperature of the exhaust gas rises from about 100°C to about 300°C.

Higher exhaust gas temperature and higher exhaust gas volume result in higher heat loss. Therefore, compared with the GGR shaft furnace ignited with natural gas, the GGR shaft furnace designed according to the prior art has only 3.3 MJ/Nm ³ When the calorific value gas is ignited, it needs about 20% more heat energy or fuel.

Due to the larger exhaust gas volume, compared with the GGR shaft furnace ignited by natural gas, the pressure loss of the GGR shaft furnace designed according to the prior art is increased by approximately 35% when operating with gas with a heating value of ^{only 3.3 MJ/Nm 3.} Likewise, the need to compress gas and process air will result in higher electrical energy requirements.

A method is known from EP 1 634 026 B1, which reduces the aforementioned disadvantages. However, the disadvantage of this method is that it requires a large and expensive hot gas heat exchanger, which can also incorporate dust due to the high operating temperature.

Summary of the invention

Starting from this, the object of the present invention is to provide a method for operating a GGR shaft furnace in which the above-mentioned disadvantages are overcome.

According to the present invention, this task is solved by a method having the characteristics of the independent method claim 1 and by a device having the characteristics of the independent device claim 9. Advantageous improvements are obtained from the scope of the dependent patent application.

According to a first aspect, the present invention includes a method of burning and cooling a material such as carbonate rock in a co-current-counter-current-regeneration-shaft furnace having two shafts (operating alternately as a combustion shaft and a regeneration shaft), wherein The material flows through the preheating zone, at least one combustion zone and cooling zone, and reaches the material outlet. The fuel is fed into the respective shaft in the preheating zone or above the preheating zone, so that the fuel is heated in the preheating zone before entering the combustion zone. In this context, "above the preheating zone" should be understood as upstream of the preheating zone in the direction of material flow. Preferably, the fuel is only supplied in or above the preheating zone. The fuel is, for example, gas, such as blast furnace gas, which has a heating value of ^{less than 6 MJ/Nm 3.}

This makes possible a uniform gas and temperature distribution in the shaft, which is a prerequisite for the production of good and uniform product quality.

The co-current-counter-current regeneration shaft furnace for burning and cooling materials such as carbonate rock has at least two shafts, preferably arranged parallel to each other and vertically. The shafts can alternately operate as combustion shafts and as regeneration shafts, wherein each shaft has a preheating zone for preheating the material, a burning zone for burning the material, and a cooling zone for cooling the material in the flow direction of the material. Each shaft preferably has a material inlet for the material to be burned into the shaft, wherein the material inlet is located in particular at the upper end of the respective shaft so that the material falls into the respective shaft due to gravity. The task of the material to be burned is performed, for example, at the same height level as the inlet of the fuel into the respective shaft. The fuel inlet is arranged above or in the preheating zone. The fuel delivery takes place especially above the preheating zone, so that the fuel, especially the gas, passes through the entire preheating zone before entering the combustion zone.

Preferably, the shafts are connected to each other in gas technology through a gas channel, so that gas can flow from one shaft to another shaft. The gas channel has the function of an overflow channel between two shafts.

The material to be burned is especially limestone or dolomite.

According to the first embodiment, the oxidizing gas is fed into the combustion zone. Preferably, only the oxidizing gas is fed into the combustion zone and not into the preheating zone. The device for introducing oxidizing gas is especially arranged inside the combustion zone. Oxidizing gas (e.g. air, oxygen-enriched air or with about 80% oxygen content or oxygen-containing gas or almost pure oxygen) is preferably fed in the preheating zone, at the entrance of the combustion zone or along the flow of the material in the combustion zone Direction to proceed. According to another embodiment, the oxidizing gas is fed into the combustion zone by a plurality of spray guns (Lanze). For example, the oxidizing gas is introduced into each shaft through a spray gun, wherein the spray gun is particularly L-shaped, evenly spaced apart from each other, and extends from the preheating zone to the combustion zone, so that the oxidizing gas is preferably in the preheating zone. The inside is heated and leaves the spray gun in the combustion zone. This provides the advantage of introducing the oxidizing gas into the combustion zone in a targeted manner, where the combustion of the gas occurs.

It is also conceivable to send oxidizing air into the shaft through at least one or more gaps in the shaft wall. These gaps extend substantially horizontally, in particular transversely to the direction of material flow, for example. The gaps form inlets for the oxidizing air to enter the respective shafts, and for example are all arranged at the same height level and in particular evenly spaced apart from each other. The advantage of this embodiment is that the diluted, curtain-like oxidizing gas flow flows downward (in the material flow direction) near or at the inner wall of the shaft, so that the CO of the fuel gas is completely burned. Instead of the gap or in addition, the spray gun described above can be provided.

Preferably, inlets for the oxidizing gas to enter are provided at a plurality of positions in the shaft. For example, the entrance is slit in the shaft wall or implemented as a gun. Such inlets are provided, for example, at a plurality of positions successive to each other in the material flow direction in the combustion zone. It is also conceivable to provide an inlet in the preheating zone, especially on the boundary between the preheating zone and the combustion zone.

According to another embodiment, the fuel, especially the gas, has ^{a calorific value of less than 6.6 MJ/Nm 3} , especially 1 MJ/Nm ³ to 7 MJ/Nm ³ , preferably 2 MJ/Nm ³ to 4 MJ/Nm ³ , most Preferably a calorific value of 3.3 MJ/Nm ^3.

According to another embodiment, a flow barrier for generating a volume of gas without the material to be burned is arranged on the transition between the preheating zone and the combustion zone or in the preheating zone or in the combustion zone, wherein there is no Oxidizing gas is introduced into the gas volume of the material to be burned. The flow barriers are, for example, beams arranged transverse to the direction of material flow. A gas volume without the material to be burned is formed under the beam, and the oxidizing gas is introduced into the gas volume. This provides the advantage of uniformly introducing and distributing the oxidizing gas into the respective shafts.

According to another embodiment, the oxidizing gas is introduced into an annular chamber arranged around the combustion zone, in particular around the transition between the preheating zone and the combustion zone. Preferably, the annular chamber is arranged concentrically around the preheating zone and/or combustion zone of one or all shafts of the GGR shaft furnace. The toroidal chamber exhibits a gas volume without the material to be burned, into which the oxidizing gas is advantageously introduced.

According to another embodiment, over the length of the combustion cycle, each shaft operates as a combustion shaft, and the following method steps are performed during the combustion cycle: a. In the time interval of the fuel delivery time, the fuel is delivered to the combustion shaft through the fuel inlet, b. In the time interval of the pre-purge time, the inert gas is delivered to the combustion shaft through the fuel inlet, c. In the time interval of the post-purge time, oxygen-depleted gas is delivered to the combustion shaft through the fuel inlet, d. Conversion furnace operation, which reverses the functions of combustion shaft and regeneration shaft. The above method steps are preferably performed sequentially in the listed order.

The inert gas is, for example, nitrogen or carbon dioxide. The inert gas is preferably introduced into the combustion shaft through the fuel inlet above the preheating zone or the preheating zone, so that the fuel gas preferably moves downward in the flow direction of the material. After the pre-purge time, there is preferably no more combustible gas mixture in or above the preheating zone of the combustion shaft. The pre-purge time is preferably a post-purge time in terms of time, in which oxygen-depleted gas (such as furnace exhaust gas) is fed into the combustion shaft at the fuel inlet of the combustion shaft, so that it is preferable that the diluted fuel gas is in the material In the direction of flow, it moves further down in the combustion shaft. At the end of the post-purge time, the environmentally harmful gas concentration in the preheating zone and above the preheating zone of the combustion shaft is preferably so low that it can be switched to other shafts still operating as regeneration shafts.

This provides the advantage that in the reverse operation mode or at the end of the loop, in which the operation as a combustion shaft or regeneration shaft is exchanged, the function of the unburned gas in the combustion zone of the combustion shaft is exchanged in the furnace shaft Complete combustion before in order to minimize the risk of explosion and prevent unacceptable emissions to the atmosphere.

According to another embodiment, during the pre-purge time and/or the post-purge time, the oxidizing gas is fed into the combustion shaft through a spray gun. As a result, the combustible gas flowing into the combustion zone from above during the pre-purge time and the post-purge time is completely burned.

The invention also relates to a co-current-counter-current-regeneration-shaft furnace for burning and cooling materials such as carbonate rock, which has two shafts which can be operated alternately as combustion shafts and as regeneration shafts , Wherein each shaft has a preheating zone for preheating the material, a combustion zone for burning the material, and a cooling zone for cooling the material in the direction of material flow. A fuel inlet is arranged above the preheating zone or in the preheating zone to allow fuel to enter respective shafts. The advantages and design solutions described above in relation to the method for operating the GGR shaft are also applicable to the GGR shaft in a corresponding manner according to the device.

According to one embodiment, in the combustion zone, a plurality of spray guns or slits are arranged in the shaft wall for feeding the oxidizing gas. The spray gun extends, for example, from the preheating zone into the combustion zone, so that the outlet of the spray gun is arranged in the combustion zone.

According to another embodiment, in the combustion zone, a plurality of gas lances or slits are arranged in the shaft wall for feeding the oxidizing gas. Preferably, as an alternative or in addition to the above-mentioned spray gun, a gas spray gun is arranged in the combustion zone and/or the cooling zone and/or in the gas passage for connecting the shaft, wherein the gas spray gun is arranged in the spray gun especially in the direction of flow of the material Downstream. The gas spray guns are arranged evenly spaced apart from each other, for example, in the combustion zone and/or the cooling zone. The introduction of oxidizing gas into another downstream area in the combustion zone and/or cooling zone ensures complete combustion of the fuel in the GGR shaft furnace.

According to another embodiment, a flow barrier is arranged on the transition between the preheating zone and the combustion zone for generating a gas volume without the material to be burned. According to another embodiment, a device for introducing the oxidizing gas into the gas volume without the material to be burned is arranged.

According to another embodiment, each shaft has its own one gas collection channel configured as an annular chamber, and wherein the gas collection channels of the shaft are connected to each other in gas technology by the gas channel. Preferably, the GGR shaft furnace has gas channels for connecting the shafts to each other in gas technology, wherein the gas channels connect, for example, the cooling zone and/or the combustion zone of the shaft to each other at one area. The gas collection channel is preferably arranged as an annular chamber surrounding the cooling zone and/or the combustion zone of each shaft.

This provides the advantages of a more uniform gas and temperature distribution in the shaft and thus a better product quality with lower emissions of harmful substances. Another advantage is that the unburned gas flowing into the gas channel from the preheating zone is better post-combusted there together with the cooling air delivered to the combustion shaft, because the gas channel has a significantly larger volume.

Detailed description of the preferred embodiment

Figure 1 shows a GGR shaft furnace 10 with two parallel and vertically oriented shafts 12, 14. Each shaft 12, 14 has a material inlet 16, 18, for the material to be burned into the respective shaft 12, 14 of the GGR shaft furnace. The material inlets 16, 18 are exemplarily arranged at the upper ends of the respective shafts 12, 14 so that the material passes through the material inlets 16, 18 and falls into the shafts 12, 14 due to gravity.

Each shaft 12, 14 additionally has a fuel inlet 20, 22 at its upper end for the gas to enter. The fuel inlets 20, 22 are exemplarily arranged at the same height level as the material inlets 16, 18.

At the lower end of each shaft 12, 14 is a material outlet 24, 26 for discharging the material burned in the respective shaft 12, 14. Each shaft 12, 14 has a cooling air inlet 28, 30 at its lower end for allowing cooling air to enter the corresponding shaft 12, 14. In the operation of the GGR shaft furnace 10, the material to be burned flows through the shafts 12, 14 from the top to the bottom, and the cooling air flows through the shafts from the bottom to the top and countercurrent to the material. The furnace exhaust gas is discharged from the respective shaft 12, 14 through the material inlet 16, 18 or through the fuel inlet 20, 22 or a gas outlet separate therefrom, for example.

Below the material inlets 16, 18 and the fuel inlets 20, 22, the preheating zones 32, 34 of the respective shafts 12, 14 are connected in the flow direction of the material. In the preheating zones 32, 34, materials and fuels are preferably preheated to about 700°C. Preferably, each shaft 12 is filled with the material to be burned up to the upper boundary surface 36, 38 of the preheating zone 32, 34. Materials and fuels, especially gas, are preferably fed into the respective shafts above the preheating zones 32, 34. At least a part of the preheating zones 32, 34 and the parts of the respective shafts 12, 14 connected to the preheating zone in the material flow direction are surrounded by a refractory lining 44, for example.

A plurality of spray guns 40, 42 are optionally arranged in the preheating zones 32, 34 and each is used as an oxidizing gas (for example, oxygen-containing air, especially oxygen-enriched air, or a gas with an oxygen content of about 80%, or almost pure Oxygen) entrance. FIG. 1 also shows a cross-sectional view of the GGR shaft furnace 10 at the height level of the spray guns 40 and 42. For example, twelve spray guns 40, 42 are arranged in each shaft 12, 14 and are substantially evenly spaced apart from each other. The spray guns 40, 42 have, for example, an L-shape, and preferably extend in the horizontal direction into the respective shaft 12, 14 and in the shaft 12, 14 in the vertical direction, especially in the direction of flow of the material. The ends of the spray guns 40, 42 of the shafts 12, 14 are preferably arranged at the same height level. Preferably, the planes on which the spray guns 40, 42 are arranged are the lower boundary surfaces 46, 48 of the respective preheating zones 32, 34, respectively. As an alternative to or in addition to the spray guns 40, 42, the slits in the shaft wall can also be configured as inlets for oxidizing air to enter the shaft.

The preheating zones 32, 34 connect the combustion zones 50, 52 in the direction of material flow. In this combustion zone, the fuel is burned, and the preheated material is burned at a temperature of about 1000°C. The oxidizing gas sent into the combustion zones 50 and 52 through the spray guns 40 and 42 realizes the combustion of the fuel in the combustion zones 50 and 52. In the combustion zone 50, 52 and/or the cooling zone 60, 62, a plurality of gas spray guns 64, 66 are optionally provided, which extend to the combustion zone 50, at a position downstream of the aforementioned spray guns 40, 42 in the material flow direction. 52 and/or cooling zone 60, 62, and used to allow oxidizing gas to enter the combustion zone 50, 52 and/or cooling zone 60, 62. The gas lances 64, 66 are arranged, for example, in the lower region of the combustion zone close to the lower boundary surfaces 56 and 58 of the combustion zone 50 and/or in the upper region of the cooling zone 60, 62 close to the lower boundary of the combustion zone 50, 52. It is also conceivable that, as shown in FIG. 1, the gas spray guns 64 and 66 are arranged in the cooling zones 60 and 62.

In addition, the GGR shaft furnace 10 has a gas channel 54 for connecting the two shafts 12, 14 to each other in gas technology. The lower boundary surfaces 56, 58 of the combustion zones 50, 52, especially the ends of the combustion zones 50, 52 are preferably arranged on the upper height level of the gas channel 54. In the respective shafts 12, 14, cooling zones 60, 62 are connected at the combustion zones 50, 52 along the material flow direction, and the cooling zone extends to the material outlets 24, 26 or discharge devices 68, 70 of the respective shafts. The material is cooled to about 100°C in the cooling zone 60, 62.

Discharge devices 68, 70 are arranged at the material outlet side ends of the respective shafts 12, 14. The discharge devices 68, 70 comprise, for example, horizontal plates, which allow the material to pass laterally between the discharge devices 68, 70 and the shell wall of the GGR shaft furnace. The discharge device 68, 70 is preferably implemented as a push-type workbench or a rotary workbench or a workbench with a push-type reamer. This achieves a uniform passing speed of the combustion material through the furnace shafts 12, 14.

In the operation of the GGR shaft furnace 10, one of the shafts 12, 14 is active (aktiv), and the other of the shafts 12, 14 is passive (passiv). The active shafts 12, 14 are called combustion shafts, and the passive shafts 12, 14 are called regeneration shafts. The GGR shaft furnace 10 is operated periodically, and the usual number of cycles is 75 to 150 cycles per day. After the end of the cycle time, the functions of the shafts 12, 14 are exchanged. This process is repeated continuously. Through the material inlets 16, 18, alternate materials such as limestone or dolomite are fed into the shafts 12, 14 each operating as a combustion shaft. In the shafts 12, 14 operating as combustion shafts, fuel gas, such as blast furnace gas, is introduced into the combustion shafts through the fuel inlets 20, 22, wherein the fuel inlets 20, 22 are used as exhaust gas outlets in the regeneration shafts. The fuel gas is heated to a temperature of about 700°C in the preheating zones 32, 34 of the combustion shaft.

Through the spray guns 40, 42, an oxidizing gas, such as air, oxygen-enriched air or oxygen, is delivered in the combustion shaft. However, an oxidizing gas with a high oxygen content is preferred, and an oxidizing gas with an oxygen content greater than 80% by volume is most preferred. By this method, the amount of gas flowing through the combustion zone 50, 52 and through the preheating zone 32, 34 of the regeneration shaft is significantly reduced, wherein the gas flowing through the preheating zone 32, 34 of the regeneration shaft does not contain excess heat, and preferably It has an exhaust gas temperature of about 100°C. Due to the small amount of gas, the pressure loss of the entire furnace is significantly reduced, which results in a significant saving of electrical energy for the process gas compressor.

Fig. 2 shows another embodiment of the GGR shaft furnace 10 with two parallel shafts 12, 14, wherein the GGR shaft furnace basically corresponds to the GGR shaft furnace 10 of Fig. 1. For the sake of clarity, some reference numerals that have been explained in FIG. 1 are omitted. Unlike the GGR shaft furnace 10 of FIG. 1, the GGR shaft furnace 10 of FIG. 2 has a circular cross section. However, all cross-sectional shapes are conceivable, such as circular, elliptical, quadrilateral or polygonal. In addition, the GGR shaft furnace 10 of FIG. 2 has a gas collection channel 82, 84, which is configured as an annular chamber. The gas collection channel preferably extends circumferentially around the lower area of the combustion zone 50, 52, especially below the gas lance 64, 66. Each shaft 12, 14 has a gas collection channel 82, 84, respectively, wherein the gas collection channel 82, 84 is arranged at the height level of the gas channel 54 for connecting the two shafts 12, 14. The gas collection channels 82, 84 of the two shafts 12, 14 are connected to one another in gas technology, in particular via a gas channel 54. In particular, the gas collection channel 82 is connected to the cooling zones 60 and 62 in gas technology, so that the cooling gas at least partially flows into the gas collection channel 82.

This configuration advantageously leads to a more uniform gas and temperature distribution in the shafts 12, 14, and thereby leads to better product quality and less pollutant emissions. Another advantage of this configuration is that the possibly unburned gas flowing from the preheating zone 32, 34 into the gas channel 54 is better post-burned there together with the cooling air delivered to the combustion shaft, because the gas channel volume is significantly larger. Big.

FIG. 3 shows another embodiment of the GGR shaft furnace 10 with two parallel shafts 12, 14, wherein the GGR shaft furnace is basically the same as the GGR shaft furnace 10 in FIG. 1. For the sake of clarity, some reference numerals that have been explained in FIG. 1 are omitted. Unlike the GGR shaft furnace 10 of FIG. 1, the GGR shaft furnace 10 of FIG. 3 does not have spray guns 40 and 42. Gas spray guns 64, 66 are only provided in the combustion zone 50, 52 and/or the cooling zone 60, 62. In addition, the GGR shaft furnace 10 of FIG. 3 has flow barriers, especially beams 86, 88, oriented transversely to the material flow direction in each preheating zone 32, 34. Below the beams 86, 88, an oxidizing gas, such as air, oxygen-enriched air, oxygen, or an oxidizing gas with an oxygen content of at least 80%, is introduced.

FIG. 4 shows another embodiment of the GGR shaft furnace 10 with two parallel shafts 12, 14, wherein the GGR shaft furnace is basically the same as the GGR shaft furnace 10 in FIG. 2. For the sake of clarity, some reference numerals that have been explained in FIG. 2 are omitted. Unlike the GGR shaft furnace 10 of FIG. 2, the GGR shaft furnace 10 of FIG. 4 does not have spray guns 40 and 42. The GGR shaft furnace 10 of FIG. 4 has another annular chamber 90, 92, which extends around the lower region of a respective preheating zone 32, 34. The annular chambers 90, 92 are connected to the combustion zone in terms of gas technology and, for example, show areas in which there is no material to be burned. In the annular chambers 90, 92, an oxidizing gas, such as air or oxygen-enriched air or oxygen, is preferably delivered, but an oxidizing gas with a high oxygen content is preferred, and an oxidizing gas with an oxygen content greater than 80% by volume is most preferred.

The GGR shaft furnaces of FIGS. 1 to 4 exemplarily have two shafts 12, 14 each. It is also conceivable to set up three or more shafts connected to each other in the GGR shaft furnace. The gas spray guns 64 and 66 shown in FIGS. 1 to 4 may, for example, replace the gas spray gun shown or be additionally arranged in the gas channel 54 so as to directly send the oxidizing gas into the gas channel.

Each shaft 12, 14 of the GGR shaft furnace 10 operates as a combustion shaft during one combustion cycle, and then operates as a regeneration shaft during one regeneration cycle.

Figure 5 shows the time flow in a combustion cycle. The fuel cycle time 72 is divided into a fuel delivery time 74, a pre-purge time 76, a post-purge time 78, and a switching time 80. In the pre-purge time 76, immediately after the fuel delivery is cut off, an inert gas, such as nitrogen or carbon dioxide, is delivered at the fuel inlets 20, 22 of the combustion shaft, and thereby the fuel gas is preferably directed downward in the flow direction of the material. move. At the end of the pre-purge time 76, it is preferable that there is no more combustible gas mixture in or above the preheating zone 32, 34 of the combustion shaft. In time, the pre-purge time 76 is followed by a post-purge time 78, in which oxygen-depleted gas, such as furnace exhaust gas, is fed into the combustion shaft at the fuel inlets 20, 22 of the combustion shaft, whereby the diluted combustion shaft is preferred. The gas further moves downward in the combustion shaft in the direction of material flow. At the end of the post-purge time 78, the concentration of harmful gases inside and above the preheating zones 32, 34 of the combustion shaft is preferably so small that it can be switched to other shafts 12 that are still operating as regeneration shafts. , 14 in. Preferably, during the pre-purge time 76 and the post-purge time 78, the oxidizing gas is introduced into the combustion shaft especially continuously through the spray guns 40, 42 so as to flow into the combustion zone from above during the pre-purge time and the post-purge time. The combustible gas in 50 and 52 burns completely.

The above-mentioned method for operating the GGR shaft 10 provides the advantage that in the reverse operation mode or at the end of the cycle, the shafts 12, 14 that are exchanged as combustion shafts or regeneration shafts operate in the combustion zone 50, 14 of the combustion shaft. The unburned gas in 52 is preferably completely burned before the function of the furnace shaft is exchanged in order to minimize the risk of explosion and prevent unacceptable emissions to the atmosphere.

It is also possible to operate the above-mentioned GGR shaft furnace 10, especially during the start-up phase, in such a way that the oxidizing gas is fed into the respective shafts 12, 14 through the fuel inlets 20, 22, wherein the fuel, especially gas, passes through the spray gun. 40, 42 are fed into the transition between the preheating zone 32, 34 and the combustion zone 50, 52.

10: GGR shaft furnace 12, 14: shaft 16,18: Material entrance 20, 22: Fuel inlet 24, 26: Material export 28, 30: cooling air inlet 32, 34: preheating zone 36, 38: The upper boundary surface of the preheating zone 40, 42: spray gun 44: Refractory lining 46, 48: The lower boundary surface of the preheating zone/the upper boundary surface of the combustion zone 50, 52: Burning zone 54: Gas Channel 56, 58: The lower boundary surface of the combustion zone/the upper boundary surface of the cooling zone 60, 62: cooling zone 64, 66: gas spray gun 68, 70: discharge device 72: Burning cycle time 74: Fuel delivery time 76: Pre-purge time 78: post purge time 80: Conversion time 82, 84: gas collection channel 86, 88: beam 90, 92: ring room

Hereinafter, the present invention will be explained in detail with reference to the accompanying drawings with the aid of a plurality of embodiments. Fig. 1 shows a schematic diagram of a GGR shaft furnace according to an embodiment in longitudinal and cross-sectional views. Fig. 2 shows a schematic diagram of a GGR shaft furnace according to another embodiment in longitudinal and cross-sectional views. Fig. 3 shows a schematic diagram of a GGR shaft furnace according to another embodiment in longitudinal and cross-sectional views. Fig. 4 shows a schematic diagram of a GGR shaft furnace according to another embodiment in a longitudinal sectional view. Fig. 5 shows a schematic diagram of a time flow in a shaft operating as a combustion shaft during a combustion cycle according to an embodiment.

10: GGR shaft furnace

12, 14: shaft

16,18: Material entrance

20, 22: Fuel inlet

24, 26: Material export

28, 30: cooling air inlet

32, 34: preheating zone

36, 38: The upper boundary surface of the preheating zone

40, 42: spray gun

44: Refractory lining

46, 48: The lower boundary surface of the preheating zone/the upper boundary surface of the combustion zone

50, 52: Burning zone

54: Gas Channel

56, 58: The lower boundary surface of the combustion zone/the upper boundary surface of the cooling zone

60, 62: cooling zone

64, 66: gas spray gun

68, 70: discharge device

Claims (15)

A method for burning and cooling materials such as carbonate rock in a co-current-counter-current-regeneration-shaft type shaft furnace, the co-current-counter-current-regeneration-shaft type shaft furnace has alternately serving as a combustion shaft and a regeneration shaft Two shafts in operation, where the material flows through the preheating zone, at least one combustion zone and cooling zone to the material outlet, It is characterized by Fuel delivery takes place in the preheating zone or above the preheating zone, so that the fuel is heated in the preheating zone before entering the combustion zone. The method of claim 1, wherein the oxidizing gas is fed into the combustion zone. The method of claim 1 or 2, wherein the fuel has ^{a calorific value less than 6.6 MJ/Nm 3} , especially 1 MJ/Nm ³ to 7 MJ/Nm ³ , preferably 2 MJ/Nm ³ to 4 MJ/Nm ^{3. The} most preferred calorific value is 3.3 MJ/Nm. The method according to any one of claims 1 to 3, wherein the oxidizing gas is fed into the combustion zone through a plurality of spray guns or slits in the shaft wall. The method according to any one of claims 1 to 4, wherein a flow barrier is arranged at the transition portion between the preheating zone and the combustion zone for generating a volume area without material to be burned, and removing The oxidizing gas is fed into the volume area. The method according to any one of claims 1 to 5, wherein the oxidizing gas is introduced into an annular chamber arranged around the combustion zone, especially around the transition between the preheating zone and the combustion zone middle. Such as the method of any one of claims 1 to 6, wherein in the time length of the combustion cycle, each shaft operates as a combustion shaft, and the following method steps are performed during the combustion cycle: a. In the time interval of the fuel delivery time, the fuel is delivered to the combustion shaft through the fuel inlet, b. During the pre-purge time, the inert gas is delivered to the combustion shaft through the fuel inlet, c. During the post-purge time, oxygen-depleted gas is delivered to the combustion shaft through the fuel inlet, d. Conversion furnace operation, which reverses the functions of combustion shaft and regeneration shaft. Such as the method of claim 7, wherein during the pre-purge time and/or the post-purge time, the oxidizing gas is sent into the combustion shaft through a gap in the spray gun and/or the shaft wall. A co-current-counter-current-regeneration-shaft furnace for burning and cooling materials such as carbonate rock. The co-current-counter-current-regeneration-shaft furnace has two shafts, which can alternately serve as Combustion shafts and operate as regeneration shafts, wherein each shaft has a preheating zone for preheating the material, a combustion zone for burning the material, and a cooling zone for cooling the material in the direction of material flow, It is characterized by A fuel inlet is arranged above the preheating zone or in the preheating zone to allow fuel to enter respective shafts. Such as the co-current-counter-current-regeneration-shaft furnace of claim 9, wherein, in the combustion zone, a plurality of spray guns or slits are arranged in the shaft wall for feeding the oxidizing gas. The same-flow-counter-flow-regeneration-shaft furnace according to claim 9 or 10, wherein in the combustion zone, in the cooling zone and/or in the gas passage connecting the shaft, a plurality of gases are arranged Spray gun, used to send oxidizing gas. The co-current-counter-current-regeneration-shaft furnace as in any one of claims 9 to 11, wherein a flow barrier is arranged at the transition between the preheating zone and the combustion zone to generate a volume area without materials to be burned . The same flow-counter-flow-regeneration-shaft furnace as in any one of claims 9 to 11, wherein an annular chamber is constructed around the transition between the preheating zone and the combustion zone, so that no material to be burned is constructed in the annular chamber The volume area. The same-flow-counter-flow-regeneration-shaft furnace as in claim 12 or 13, wherein a device for introducing oxidizing gas into a volume area where there is no material to be burned is arranged. The same-flow-counter-flow-regeneration-shaft furnace according to any one of claims 9 to 14, wherein each shaft has a gas collection channel, the gas collection channel is configured as an annular chamber, and wherein the shaft The gas collection channels are connected to each other in gas technology through gas channels.

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